This vertical grow in San Jose, Calif., shows plenty of room between racks for easy access for plant inspection.
Photo by Jack Hutch

If you’re looking to implement multiple tiers of growing in your indoor cultivation facility, follow these pointers to ensure you’re properly set up for vertical farming success.

1. Use LED lights that cover the entire plant canopy evenly, at close range. (Other light types would burn the plants at close range.) Many LED lights have much narrower physical dimensions than a typical 4-foot by 4-foot grow-tray footprint. This means they must have 12 to 24 inches of clearance above the plants to light the canopy evenly, corner to corner. In a vertical setup, that's a lot of unnecessarily wasted space. It's more convenient to access each tier when the tiers are closer together. Easier access means better plant care, and thus improved quantity and quality.

2. Beware of implementing more than two tiers when first beginning. When you have two tiers, you can easily stay within local code compliance requirements when it comes to the structural stability of mobile racking systems, as well as the rules for worker safety. Unless the tiers are very tightly packed, the line between a second and third tier is the line between ease and difficulty-both in terms of design and functionality. With two tiers of 4 feet to 5 feet each, and the lowest tier raised 1 foot off the ground, access to the second tier can be accomplished with a rolling ladder, whereas three tiers would require a scissor lift. Further, the stratification of temperatures with three tiers starts to require a much more advanced (and costly) cooling and air-movement design.

3. Leave enough space around racks for plumbing, air movement and worker access. Growers and investors often want to maximize yields, so they pack plant rooms beyond what's reasonable. But doing so could compromise the space's healthy functionality, both for plants and workers. Remember that the grow trays in the racks will need to periodically be removed, cleaned and/or replaced. If the aisle space is too narrow, this process could be frustratingly inconvenient.

4. In the early design phase, plan how to manage wastewater. Each municipality differs regarding what nutrient waste can go down the drain. Floor drains are the most convenient and inexpensive method of discarding water, but some localities require the nutrient-rich water be treated prior to discarding. This will require pumps and holding tanks for runoff. With vertical mobile racking systems, drainage collection is more complicated than with single-tier systems. Get an experienced plumber involved in the design process. Wastewater management is often-overlooked and potentially costly.

5. Choose short-growing, non-stretchy strains suited toward vertical growing, so plants don't overgrow the space per tier. These strains should be flowered before they grow too tall during the vegetative stage, and height should no more than double during the first three weeks of flowering. Choose strains that are also disease resistant. Vertical farms are designed to maximize total canopy, but when half of the canopy is above head level, careful-examination time may be reduced. This could increase the chance of unnoticed mold and mildew outbreaks.

Jennifer Martin is an award-winning cultivator who specializes in indoor vertical LED system designs (MarijuanaPropagation.com).